Pacific Yellowfin Tuna (Thunnus albacares)

• Yellowfin population levels are high, but the Eastern Pacific yellowfin stock is currently subject to overfishing.
• The tuna industry, through participating governments, works within the framework of the Agreement on the International Dolphin Conservation Program to minimize dolphin bycatch in the Eastern Pacific Ocean purse seine fishery. NOAA's National Marine Fisheries Service has recently launched a new website for tracking and verifying dolphin-safe tuna products. For more information, go to www.dolphinsafe.gov.
• Yellowfin is low in saturated fat and sodium and is a very good source of protein, thiamin, selenium, and vitamin B6. For more on nutrition, see Nutrition Facts. (USDA)
• About 25% of all yellowfin tuna sold in the U.S. comes from U.S. fisheries; the rest is imported.

Sustainability Status

Biomass: Yellowfin tuna biomass (Eastern Pacific, or EPO) is 96% of the biomass needed to support maximum sustainable yield (B_MSY); Central and Western Pacific (WCPO) biomass is 17% above B_MSY.
Overfishing: Yes (EPO); No (WCPO)
Overfished: No
Fishing and habitat: The majority of yellowfin tuna are caught with purse-seine gear that fish near the surface and therefore have minimal impacts to habitat.
Bycatch: There are bycatch issues in the purse seine fishery. Yellowfin tuna are often found in association with various species of dolphin. Some fishermen have taken advantage of this by setting their nets around the dolphin herds in order to catch the large tuna beneath them. In the 1970s, dolphin mortality was estimated to be hundreds of thousands of dolphins per year. Now, after continued research, improvements in fishing gear and techniques, and adoption of international agreements, dolphin mortality has been reduced to under 1,000 dolphins annually. For more information, see NOAA's www.dolphinsafe.gov.
Aquaculture: There is currently no commercial aquaculture of yellowfin tuna in the U.S.

Science and Management

Yellowfin tuna is a highly migratory species (HMS). There are two stocks of yellowfin tuna in the Pacific Ocean, eastern Pacific Ocean (EPO) and western and central Pacific Ocean (WCPO). The Western Pacific Fishery Management Council has managed yellowfin since 1987 through the Western Pacific Pelagics FMP. The WPFMC and the Pacific Fishery Management Council (PFMC) have taken steps to better coordinate management of pelagic fisheries, which led to the development and implementation of the PFMC's West Coast HMS Fishery Management Plan (FMP) in 2004. Both councils now collaborate in the management of Pacific yellowfin tuna, and the councils and NMFS science centers in both regions work together in the preparation of stock assessment and fishery evaluation (SAFE) reports as well.

In March 2007, NOAA proposed to implement Amendment 14 to Pelagics FMP to end overfishing of WCPO yellowfin tuna. This amendment would establish federal permitting and reporting requirements for all U.S. Hawaii-based small boat commercial pelagic fishermen. This amendment also recognizes the need for internationally coordinated management actions to ensure that overfishing of yellowfin in the Pacific ends.

In addition, since highly migratory species move throughout large areas of the Pacific and are fished by many nations and gear types, management by the U.S. alone will not ensure that harvests are sustainable in the long term. The U.S. is a member of the Inter-American Tropical Tuna Commission (IATTC), which is responsible for the conservation and management of fisheries for tunas and other species taken by tuna-fishing vessels in the eastern Pacific Ocean. The IATTC manages the EPO yellowfin stock through fishing capacity limits and periodic closures of the purse seine fishery. The IATTC performs regular assessments of this stock. As a member of IATTC, the U.S. has implemented IATTC conservation and management measures for yellowfin tuna and bigeye tuna. The Western and Central Pacific Fisheries Commission (WCPFC), an intergovernmental organization to coordinate management of HMS in the western and central Pacific, was established in 2004. Congress recently ratified U.S. membership on the Commission. The WCPFC has adopted conservation and management measures for yellowfin, including limiting purse seine effort to not exceed 2004 levels in waters under their jurisdiction.

Life History and Habitat

Life history, including information on the habitat, growth, feeding, and reproduction of a species, is important because it affects how a fishery is managed. High reproductive potential in yellowfin tuna means they may respond to management actions more rapidly than species that reproduce slowly and in small numbers.

• Geographic range: Yellowfin tuna are found throughout the Pacific Ocean, roughly within latitudes 40 degrees North and 40 degrees South but most abundant between 20 degrees North and 20 degrees South.
• Habitat: Yellowfin is a tropical species, occupying the surface waters of all warm oceans. Yellowfin favor water temperatures between 64 and 88 degrees Fahrenheit. Larval and juvenile yellowfin stay in surface waters while adults are increasingly found at greater depths.
• Life span: Relatively short; likely to be a maximum of 6 to 7 years
• Food: Yellowfin are opportunistic feeders at all life stages, feeding on whatever prey is available at the time. They feed primarily during the day. Larvae feed on crustacean zooplankton. Juveniles prey on epipelagic or mesopelagic members of the oceanic community or pelagic post-larval or pre-juvenile stages of island-, reef-, or bottom-associated organisms. Adults feed on crustaceans, cephalopods (octopus, squid, etc.), and fish. Off the west coast of Baja California, Mexico, and southern California, pelagic red crab and northern anchovy are also important parts of the diet.
• Growth rate: Growth and development are rapid in the early years of life but gradually slow thereafter.
• Maximum size: 7.8 feet in length; 440 pounds in weight
• Reaches reproductive maturity: Between 2 and 3 years of age at minimum lengths of 2 and 2.26 feet for females and males, respectively
• Reproduction: Yellowfin tuna have high "fecundity" (reproductive potential) and spawn frequently. They are "serial spawners," meaning they are capable of repeating spawning almost daily, with millions of eggs per spawning event.
• Spawning season: Peak spawning during spring and fall
• Spawning grounds: Yellowfin tuna spawn over broad areas of the Pacific. They spawn throughout the year in tropical waters and seasonally at higher latitudes at water temperatures over 75 degrees Fahrenheit.
• Migrations: Yellowfin are capable of large-scale movements and move freely within the broad regions of favorable water temperature. They are known to make seasonal excursions to higher latitudes as water temperatures increase with season (the extent and nature of which is unknown).
• Predators: Predators of larval and juvenile tuna include fish, seabirds, porpoises and other animals; predators of adult tuna include marine mammals and sharks. There is also high degree of cannibalism of juvenile tunas among large yellowfin in the southern Philippines.
• Commercial or recreational interest: Both
• Distinguishing characteristics: Yellowfin have a very long second dorsal fin and anal fin, which may reach well over 20% of the fish's length. Their coloring is black metallic dark blue and changes from yellow to silver on the belly, which has about 20 broken, nearly vertical lines. The dorsal and anal fins and finlets are bright yellow.

Role in the Ecosystem

Yellowfin tuna feed opportunistically at all life stages. Large yellowfin tunas prey on crustaceans and large squid and fish species. There is a high degree of cannibalism of juvenile yellowfin tunas among large yellowfin in the southern Philippines. Larval and juvenile yellowfin are also eaten by other fish, seabirds, porpoises, and other animals; marine mammals and sharks eat adult tunas.

Additional Information

Yellowfin are known to gather around drifting flotsam, fish aggregating devices (FADs), anchored buoys, dolphin, and other large marine animals. Adults also come together in regions of elevated productivity and high zooplankton density, such as near seamounts and regions of upwelling and convergence of surface waters of different densities.

Market name: Tuna
Vernacular name: Ahi
Several other species are also marketed as Tuna.

Biomass

Biomass refers to the amount of yellowfin tuna in the ocean. Scientists cannot collect and weigh every single fish to determine biomass, so they use models to estimate it instead. These biomass estimates can help determine if a stock is being fished too heavily or if it may be able to tolerate more fishing pressure. Managers can then make appropriate changes in the regulations of the fishery.

Note: Eastern Pacific biomass is presented as biomass of yellowfin tuna age 1.5 years and older.

Landings

Landings refer to the amount of catch that is brought to land.

Note: The landings presented are domestic commercial landings.

Biomass and Landings

Are landings and biomass related? Landings are dependent on biomass, management measures in the fishery, and fishing effort.

Note: Biomass estimates for Eastern Pacific yellowfin are only available from 1975-2002.

Data sources:
Eastern Pacific biomass from Status of Yellowfin Tuna in the Eastern Pacific Ocean in 2001 and Outlook for 2002; Central and Western Pacific biomass from Stock assessment of yellowfin tuna in the western and central Pacific Ocean

Landings from NOAA's National Marine Fisheries Service (NMFS) Annual Commercial Landing Statistics Website using "TUNA, YELLOWFIN" as species and "PACIFIC"

Important Dates

1900s – Commercial and recreational harvest in the eastern Pacific Ocean begins
1950 – IATTC established by international convention
1991 – Amendment 4 to the Pelagics Fishery Management Plan (FMP) establishes a 3-year moratorium on new entry into the Hawaii-based domestic longline fishery, limiting the volume of bigeye and yellowfin tuna that could be caught and landed by limiting the number of longline fishing vessels
1992 – Amendment 5 to the Pelagics FMP establishes a domestic longline vessel exclusion zone around the Main Hawaiian Islands and Guam to prevent gear conflicts and vessel safety issues arising from interactions between longline vessels and smaller fishing boats. Although not specifically aimed at yellowfin, the amendment has a conservation effect by placing those yellowfin tunas within the closed areas out of the reach of longline gear.
1992 – Amendment 6 to the Pelagics FMP includes tunas and related species in the management unit, allowing yellowfin to be subject to specific management and conservation measures
1994 – Amendment 7 to the Pelagics FMP institutes a limited entry program for the Hawaii-based longline fishery, which has the largest domestic catches of Pacific yellowfin under the WPFMC's jurisdiction
1999 – The Agreement on the International Dolphin Conservation Program, a legally binding instrument for dolphin conservation and ecosystem management in the eastern tropical Pacific Ocean, comes into force
2004 – NMFS approves the Pacific Fishery Management Council's FMP for West Coast Highly Migratory Species (HMS) fisheries
2004 – Western and Central Pacific Fisheries Commission (WCPFC) established
2007 – Rule proposed to implement Amendment 14 to the Pelagics FMP to end overfishing of yellowfin tuna in the western and central Pacific; in the public review stage
2007 – U.S. becomes a member of the WCPFC

Notes and Links

General Information:
Pacific Fishery Management Council Background on Highly Migratory Species

Pacific Fishery Management Council Highly Migratory Species Fact Sheet

Western Pacific Fishery Management Council Reports: Important Pelagic Fishes of the Pacific

Inter-American Tropical Tuna Commission

Western and Central Pacific Fisheries Commission

Fishery Management:
Pacific Fishery Management Council Highly Migratory Species Fishery Management Plan

Western Pacific Fishery Management Council Fishery Management Plan for Pelagic Fisheries of the Western Pacific Region

Stock Assessments:
Status of Yellowfin Tuna in the Eastern Pacific Ocean in 2001 and Outlook for 2002

Western Pacific Fishery Management Council Pelagic Fisheries of the Western Pacific Region 2005 Annual Report

Pacific Fishery Management Council Stock Assessment and Fishery Evaluation Document (SAFE) Status of the U.S. West Coast Fisheries for HMS through 2005 (2006) 

Scientific Committee of the Western and Central Pacific Fisheries Commission 2007 Stock assessment of yellowfin tuna in the western and central Pacific Ocean